Hi Russel, On Sun, 2016-07-10 at 00:19 -0700, Russell Senior wrote: > > > > > > > > > > > > > > > > > > > > > > > > > > "Alexey" == Alexey Brodkin <Alexey.Brodkin at synopsys.com> writes: > Alexey> Hi Aaron, > Alexey> On Sat, 2016-07-09 at 07:47 -0400, Aaron Z wrote: > > > > > > > > On Sat, Jul 9, 2016 at 4:37 AM, Alexey Brodkin > > > <Alexey.Brodkin at synopsys.com> wrote: > > > > > > > > > > > > Hello, > > > > > > > > I was playing with quite simple bridged setup on different boards > > > with > very recent kernels (4.6.3 as of this writing) and found one > > > interesting > behavior that I cannot yet understand and googling > > > din't help here as well. > > > > > > > > > > > > My setup is pretty simple: > > > > -------------???????------------------???????------------------------- > > > > > > > > > > > > > > > > > > > HOST??????|???????| "Dumb AP"??????|???????| Wireless > > > client???????| > > with DHCP |<----->(eth0)?????(wlan0)<----->| > > > attempting to?????????| > > server????|???????|????\ br0 > > > /?????|???????| get settings via DHCP | > > > > -------------???????------------------???????------------------------- > > > > > > > > > > > > * HOST is my laptop with DHCP server that works for sure.??> * > > > "Dumb AP" is a separate board (I tried ARM-based Wandboard and > > > ARC-based > ? AXS10x boards but results are exactly the same) with > > > wired (eth0) and wireless > ? (wlan0) network controllers bridged > > > together (br0). That "br0" bridge flawlessly > ? gets its settings > > > from DHCP server on host.??> * Wireless client could be either a > > > smatrphone or another laptop etc but > ? what's important it should > > > be configured to get network settings by DHCP as well. > > > > > > > > > > > > So what happens "br0" always gets network settings from DHCP server > > > on HOST.??> That's fine. But wireless client only reliably gets > > > settings from DHCP server > if IPv6 is enabled on "Dumb AP" board. If > > > IPv6 is disabled I may see that > wireless client sends "DHCP > > > Discover" then server replies with "DHCP Offer" but > that offer > > > never reaches wireless client. > > > > > > > > > Do you have WDS enabled? If not, DHCP has issues in that scenario: > > > https://wiki.openwrt.org/doc/howto/clientmode > If the Dumb AP's wireless interface is in ap-mode, then this shouldn't > be an issue.??It's only client-mode interfaces that have trouble with bridging. > > I'd suggest running tcpdump on the Dumb AP's wireless interface and the > client's wireless interface and see which of them sees the various parts > of the DHCP handshake. So I did but for DHCP server and wireless client (had no tcpdump on Dump AP at the moment). That's what I see on the server: ----------------------------->8------------------------------- No. Time????????Source?????Destination??????Protocol Length Info ?3 0.151181000??0.0.0.0????255.255.255.255??DHCP?????342????DHCP Discover - Transaction ID 0x31dc321f 11 2.760796000??10.42.0.1??10.42.0.13???????DHCP?????342????DHCP Offer????- Transaction ID 0x31dc321f 14 5.220985000??0.0.0.0????255.255.255.255??DHCP?????342????DHCP Discover - Transaction ID 0x31dc321f 15 5.221150000??10.42.0.1??10.42.0.13???????DHCP?????342????DHCP Offer????- Transaction ID 0x31dc321f 23 15.649835000 0.0.0.0????255.255.255.255??DHCP?????342????DHCP Discover - Transaction ID 0x31dc321f 24 15.650017000 10.42.0.1??10.42.0.13???????DHCP?????342????DHCP Offer????- Transaction ID 0x31dc321f 32 25.648589000 0.0.0.0????255.255.255.255??DHCP?????342????DHCP Discover - Transaction ID 0x31dc321f 33 25.648758000 10.42.0.1??10.42.0.13???????DHCP?????342????DHCP Offer????- Transaction ID 0x31dc321f 43 35.864567000 0.0.0.0????255.255.255.255??DHCP?????342????DHCP Discover - Transaction ID 0x31dc321f 48 38.832837000 10.42.0.1??10.42.0.13???????DHCP?????342????DHCP Offer????- Transaction ID 0x31dc321f ----------------------------->8------------------------------- That's on the wireless client: ----------------------------->8------------------------------- No.??Time???????????Source???Destination??????Protocol Length Info 1171 94.192971000???0.0.0.0??255.255.255.255??DHCP?????342????DHCP Discover - Transaction ID 0x31dc321f 1182 99.263686000???0.0.0.0??255.255.255.255??DHCP?????342????DHCP Discover - Transaction ID 0x31dc321f 1185 109.692642000??0.0.0.0??255.255.255.255??DHCP?????342????DHCP Discover - Transaction ID 0x31dc321f 1186 119.691474000??0.0.0.0??255.255.255.255??DHCP?????342????DHCP Discover - Transaction ID 0x31dc321f 1190 129.907507000??0.0.0.0??255.255.255.255??DHCP?????342????DHCP Discover - Transaction ID 0x31dc321f ----------------------------->8------------------------------- I'll try to capture data from Dumb AP sometime soon and will reply to the thread. -Alexey
